Twenty two miners are reported to have died, and another two have reportedly been injured, in an incident at the Nantong Mining Company operated Yanshitai Coal Mine in the south of the Chongqing Municipality in southwest China, that occurred at about 3.40 pm local time on Tuesday 3 May 2014. The precise nature of the incident is unclear, being described only as a 'gas-incident' by local authorities. It is understood that there were 28 miners in the shaft at the time of the incident, and that all have been accounted for.
The approximate location of the Yanshitai Coal Mine. Google Maps.
Coal is formed when buried organic material, principally wood, in heated and pressurized, forcing off hydrogen and oxygen (i.e. water) and leaving more-or-less pure carbon. Methane is formed by the decay of organic material within the coal. There is typically little pore-space within coal, but the methane can be trapped in a liquid form under pressure. Some countries have started to extract this gas as a fuel in its own right. When this pressure is released suddenly, as by mining activity, then the methane turns back to a gas, expanding rapidly causing, an explosion. This is a bit like the pressure being released on a carbonated drink; the term 'explosion' does not necessarily imply fire in this context, although as methane is flammable this is quite likely.
Coal is also comprised more or less of pure carbon, and therefore reacts freely with oxygen (particularly when in dust form), to create carbon dioxide and (more-deadly) carbon dioxide, while at the same time depleting the supply of oxygen. This means that subterranean coal mines need good ventilation systems, and that fatalities can occur if these break down.
See also...
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Ten coal miners are now known to have died in a flood at the Zhengsheng Coal Mine in Shanxi Province, northern China, at about...
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